Re: [PATCH V3 5/9] iio: imu: inv_icm42607: Add Temperature Support in icm42607

[David Lechner <dlechner@baylibre.com>]

On 3/30/26 2:58 PM, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>
> 
> Add functions for reading temperature sensor data.
> 
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
> ---
>  drivers/iio/imu/inv_icm42607/inv_icm42607.h   |  3 +
>  .../iio/imu/inv_icm42607/inv_icm42607_core.c  | 17 ++++
>  .../iio/imu/inv_icm42607/inv_icm42607_temp.c  | 81 +++++++++++++++++++
>  .../iio/imu/inv_icm42607/inv_icm42607_temp.h  | 30 +++++++
>  4 files changed, 131 insertions(+)
>  create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
>  create mode 100644 drivers/iio/imu/inv_icm42607/inv_icm42607_temp.h
> 
> diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607.h b/drivers/iio/imu/inv_icm42607/inv_icm42607.h
> index 5530fd3bc03f..086848c8fd3b 100644
> --- a/drivers/iio/imu/inv_icm42607/inv_icm42607.h
> +++ b/drivers/iio/imu/inv_icm42607/inv_icm42607.h
> @@ -433,6 +433,9 @@ extern const struct dev_pm_ops inv_icm42607_pm_ops;
>  
>  u32 inv_icm42607_odr_to_period(enum inv_icm42607_odr odr);
>  
> +int inv_icm42607_set_temp_conf(struct inv_icm42607_state *st, bool enable,
> +			       unsigned int *sleep_ms);
> +
>  int inv_icm42607_debugfs_reg(struct iio_dev *indio_dev, unsigned int reg,
>  			     unsigned int writeval, unsigned int *readval);
>  
> diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> index 344071089042..735a262dc103 100644
> --- a/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> +++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_core.c
> @@ -164,6 +164,23 @@ static int inv_icm42607_set_pwr_mgmt0(struct inv_icm42607_state *st,
>  	return 0;
>  }
>  
> +int inv_icm42607_set_temp_conf(struct inv_icm42607_state *st, bool enable,
> +			       unsigned int *sleep_ms)
> +{
> +	unsigned int val;
> +	int ret;
> +
> +	val = INV_ICM42607_TEMP_CONFIG0_FILTER(INV_ICM42607_FILTER_BW_34HZ);
> +	ret = regmap_update_bits(st->map, INV_ICM42607_REG_TEMP_CONFIG0,
> +				 INV_ICM42607_TEMP_CONFIG0_FILTER_MASK, val);
> +	if (ret)
> +		return ret;
> +
> +	return inv_icm42607_set_pwr_mgmt0(st, st->conf.gyro.mode,
> +					  st->conf.accel.mode, enable,
> +					  sleep_ms);
> +}
> +
>  int inv_icm42607_debugfs_reg(struct iio_dev *indio_dev, unsigned int reg,
>  			     unsigned int writeval, unsigned int *readval)
>  {
> diff --git a/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
> new file mode 100644
> index 000000000000..b42eb78cd960
> --- /dev/null
> +++ b/drivers/iio/imu/inv_icm42607/inv_icm42607_temp.c
> @@ -0,0 +1,81 @@
> +// SPDX-License-Identifier: GPL-2.0-or-later
> +/*
> + * Copyright (C) 2026 InvenSense, Inc.
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/mutex.h>
> +#include <linux/pm_runtime.h>
> +#include <linux/regmap.h>
> +#include <linux/iio/iio.h>
> +
> +#include "inv_icm42607.h"
> +#include "inv_icm42607_temp.h"
> +
> +static int inv_icm42607_temp_read(struct inv_icm42607_state *st, s16 *temp)
> +{
> +	struct device *dev = regmap_get_device(st->map);
> +	__be16 *raw;
> +	int ret;
> +
> +	PM_RUNTIME_ACQUIRE_AUTOSUSPEND(dev, pm);
> +	if (PM_RUNTIME_ACQUIRE_ERR(&pm))
> +		return -ENXIO;
> +
> +	guard(mutex)(&st->lock);
> +
> +	ret = inv_icm42607_set_temp_conf(st, true, NULL);
> +	if (ret)
> +		return ret;
> +
> +	raw = (__be16 *)&st->buffer[0];

Can we make buffer __be16 buffer[] to avoid cast and ensure proper alignment?

> +	ret = regmap_bulk_read(st->map, INV_ICM42607_REG_TEMP_DATA1, raw, sizeof(*raw));
> +	if (ret)
> +		return ret;
> +
> +	*temp = (s16)be16_to_cpup(raw);

cast is not needed. temp is already s16.

> +	if (*temp == INV_ICM42607_DATA_INVALID)
> +		ret = -EINVAL;
> +
> +	return ret;
> +}
> +
> +int inv_icm42607_temp_read_raw(struct iio_dev *indio_dev,
> +				struct iio_chan_spec const *chan,
> +				int *val, int *val2, long mask)
> +{
> +	struct inv_icm42607_state *st = iio_device_get_drvdata(indio_dev);
> +	s16 temp;
> +	int ret;
> +
> +	if (chan->type != IIO_TEMP)
> +		return -EINVAL;
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		if (!iio_device_claim_direct(indio_dev))
> +			return -EBUSY;
> +		ret = inv_icm42607_temp_read(st, &temp);
> +		iio_device_release_direct(indio_dev);
> +		if (ret)
> +			return ret;
> +		*val = temp;
> +		return IIO_VAL_INT;
> +	/*
> +	 * T°C = (temp / 128) + 25
> +	 * Tm°C = 1000 * ((temp * 100 / 12800) + 25)
> +	 * scale: 100000 / 12800 ~= 7.8125
> +	 * offset: 25000
> +	 */
> +	case IIO_CHAN_INFO_SCALE:
> +		*val = 7;
> +		*val2 = 812500;
> +		return IIO_VAL_INT_PLUS_MICRO;

Could use IIO_VAL_INT_PLUS_NANO to get more exact value.

> +	case IIO_CHAN_INFO_OFFSET:
> +		*val = 25000;
> +		return IIO_VAL_INT;
> +	default:
> +		return -EINVAL;
> +	}
> +}